// Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#pragma once
namespace pir {

class Operation;
///
/// \brief Value Iterator
///
template <typename OperandType>
class ValueUseIterator {
 public:
  ValueUseIterator(OperandType use = nullptr) : current_(use) {}  // NOLINT

  bool operator==(const ValueUseIterator<OperandType> &rhs) const {
    return current_ == rhs.current_;
  }
  bool operator!=(const ValueUseIterator<OperandType> &rhs) const {
    return !(*this == rhs);
  }

  Operation *owner() const { return current_.owner(); }

  OperandType &operator*() { return current_; }

  OperandType *operator->() { return &operator*(); }

  ValueUseIterator<OperandType> &operator++() {
    current_ = current_.next_use();
    return *this;
  }

  ValueUseIterator<OperandType> operator++(int) {
    ValueUseIterator<OperandType> tmp = *this;
    current_ = current_.next_use();
    return tmp;
  }

 protected:
  OperandType current_;
};

}  // namespace pir
